Various services have become available with the development of communications technology. For example, in a telephone system, there are many services in practical use such as call forwarding, Automatic Voice Messaging (AVM), Automatic Call Back (ACB), Enhanced Repeat Dial (ERP), and Abbreviated Dialing (AD). These services are typically presented to users by recorded announcements. Recorded announcements for such calling services are formed from spoken words, phrases, tones or periods of silence stored in separate speech files. In response to a request for such calling services, various speech files are accessed in a predetermined order to generate a complete announcement which is then presented to the caller.
Telecommunications equipment vendors support such calling services by providing multiple speech files on circuit cards along with a microprocessor controller for accessing the speech files and generating announcements. The circuit cards provide link access to the front end of a digital phone network switch. An example of such a circuit card is the NT1x80AA Enhanced Digital Recorded Announcement Machine (EDRAM) card manufactured by Northern Telecom.
Commercially available circuit cards have several shortcomings, however. The circuit cards typically have announcement fragments stored in several separate speech files. In a typical announcement, portions of the several speech files must be accessed to form a complete announcement. A telephone company seeking to implement a particular calling service must purchase all of the speech files, even though many of the fragments within the speech files do not support the desired calling feature. Furthermore, due to limited memory space on the circuit cards, the resources of an entire circuit card can be exhausted in a typical implementation of a single calling service. Thus, for each calling service implemented by a telephone company, a dedicated circuit card must be purchased. In some instances, a separate controller card must also be programmed to retrieve and assemble complete announcements from the available speech files on the circuit cards. Considering a large telephone company with many central offices, circuit cards represent a substantial equipment investment.